Learning Rust from C and Java?

I just got accepted in an internship where I'll have to program in Rust. I told them I only knew C (not C++) and Java, zero experience with Rust, but that I was willing to learn. Now that I got accepted, I'm kind of worried since is my first internship... How long will it take me to learn Rust? where should I begin? I don't want to go there and them to realized I'm incompetent and know nothing